Step 2 of 4:
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If you don't have a personal .vimrc - you could always create one.
Somewhere on your system, bundled with the documentation for vim - there will be an example .vimrc which has some sane defaults in it, which you can copy to your home folder and use as a base for your own .vimrc.
I think the example vimrc is somewhere like:
/usr/share/vim/vim80/vimrc_example.vim
But to find its exact location on your machine, just try something like:
There is also an example gvimrc file, for the gui version of vim called gvimrc_example.vim.
Once you have located it, copy it to your home directory and rename it .vimrc (or .gvimrc for the GUI version of vim). Then you can make your customisations to it.
However, if modifying roots .vimrc works for you - then by all means go with that!
Step 3 of 4:
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It looks like helptags is a script that should have been installed when you installed the rest of the vim-latex suite. It looks like it will convert a couple of text files and will add them to vims built-in documentation.
This will allow you to use vims :help command to access help on whatever tools are packaged with vim-latex.
You need to run it and pass it the path to store the generated vim documentation.
So it looks like you should run:
If the above fails because you don't have a .vim/ or .vim/doc directory, you can make the directories manually:
Then try running the script again.
Or you could perhaps install the help documentation in the root .vim directory where you put your vimrc:
e.g. install the help to /.vim/doc
Which I imagine would require root permissions:
The above assumes you are using sudo in your arch installation. If not, I guess you would need to su to root before running the helptags script.
And again, if the script fails because the doc subdirectory doesn't exist in /.vim/, then use mkdir to make the subdirectory and try the helptags script again.
NOTE: I haven't looked at the installation instructions for vim-latex. I'm just going by what I can deduce from your post. It looks fairly straightforward.