These start with the installer page - the installer is known as Ubiquity, made by Ubuntu and also used by Linux Mint and some others
Before you start, if you like you can go to the Start Menu (LM) and click, on the left will be an icon for Settings, go into it and disable screensaver, to Power and switch Power saving off (I switch both to never) and if you want increase your mouse cursor size such as I have. Then go on with below
...so you start by clicking the installer (sometimes a double click) and we'll go from there.
choose your language and click continue
choose your keyboard and then continue
check to install the multimedia codecs and click continue. You can also see the blues above mounting up with the white steps to go. At the bottom.
Now this stage may take some time to complete, it has not broken - go make a cuppa tea or coffee and come back if you like.
During this stage, you may get a popup window such as I show below
I am ready to click Yes there, but it does not matter much, it is covered with the next new screenshot.
After making that choice, the codec install may still keep going on for a bit, as long as you see movement continuing like below, it's still hard at work
When the codecs are finished the next screen is where you make a choice
... and it is an important one, and note that it is different to similar ones you have seen earlier, as those were old pics.
The default is as shown, and that's where you would be dualbooting or multi-booting with Windows, Linux (one or more) and so on, if you wanted all the rest of your disk space dedicated to Linux Mint.
If you want to blow away Windows, it is the second option - erase and install.
The third option, Something else, is where you know what you are doing, and you can be more flexible with partition sizes, drives and so on.
I can't take you further for now, without installing and I already have it (Virginia Cinnamon) but while the installer is copying files you will be shown a screen where you can choose a login/user name, choose whether to encrypt or not (don't) and so on.
On completion, the installer will give you the option to continue testing (which is what you have been doing all along, apparently) or to reboot.
When you are ready to reboot do so, and it will prompt you to remove the stick and press Enter and away you go.
Cheers

Before you start, if you like you can go to the Start Menu (LM) and click, on the left will be an icon for Settings, go into it and disable screensaver, to Power and switch Power saving off (I switch both to never) and if you want increase your mouse cursor size such as I have. Then go on with below
...so you start by clicking the installer (sometimes a double click) and we'll go from there.

choose your language and click continue

choose your keyboard and then continue

check to install the multimedia codecs and click continue. You can also see the blues above mounting up with the white steps to go. At the bottom.
Now this stage may take some time to complete, it has not broken - go make a cuppa tea or coffee and come back if you like.
During this stage, you may get a popup window such as I show below

I am ready to click Yes there, but it does not matter much, it is covered with the next new screenshot.
After making that choice, the codec install may still keep going on for a bit, as long as you see movement continuing like below, it's still hard at work

When the codecs are finished the next screen is where you make a choice

... and it is an important one, and note that it is different to similar ones you have seen earlier, as those were old pics.
The default is as shown, and that's where you would be dualbooting or multi-booting with Windows, Linux (one or more) and so on, if you wanted all the rest of your disk space dedicated to Linux Mint.
If you want to blow away Windows, it is the second option - erase and install.
The third option, Something else, is where you know what you are doing, and you can be more flexible with partition sizes, drives and so on.
I can't take you further for now, without installing and I already have it (Virginia Cinnamon) but while the installer is copying files you will be shown a screen where you can choose a login/user name, choose whether to encrypt or not (don't) and so on.
On completion, the installer will give you the option to continue testing (which is what you have been doing all along, apparently) or to reboot.
When you are ready to reboot do so, and it will prompt you to remove the stick and press Enter and away you go.
Cheers