If you are not using `latexmk` or for some other reason need too add the `./src/` subfolder to laTeX search-path, here is how to do it:

### Using MiKTeX
MiKTeX makes this very easy by adding an option for that. Just add `-include-directory=./src` to your call to `pdflatex`. <br>
For building from sub folders, just add a second `-include-directory=../src` to your call.

### Using Texmaker and MiKTeX
As stated above, you just need to extend your Latex-call with the needed include path. <br>
To do this, go to _Options → config Texmaker → Commands_ <br>
change the pdflatex command to:

```bash
pdflatex -synctex=1 -interaction=nonstopmode -include-directory=./src -include-directory=../src %.tex
```

### Using VS Code with LaTeX Workshop
In VS Code you can configure your launch to set environment variables. Just edit your `settings.json`, so that your pdflatex tool contains a `env:`
(add it, if it isn't there yet). If you use the template below, you will also get some additional nice configurations. See also
[here](https://lab.it.hs-hannover.de/qxx-tul-u1/latex-template-hsh/-/snippets/111) for some additional configs.

```json
"latex-workshop.latex.tools": [
    {
        "name": "pdflatex",
        "command": "pdflatex",
        "args": [
            "-synctex=1",
            "-interaction=nonstopmode",
            "-file-line-error",
            "-aux-directory=%OUTDIR%/.aux",
            "-output-directory=%OUTDIR%",
            "%DOC%"
        ],
        "env": {
            "TEXINPUTS": "%DIR%/src/;%DIR%/../src/"
        }
    }
]
```

### On Overleaf 
As explained [here](https://www.overleaf.com/learn/latex/Questions/I_have_a_lot_of_.cls%2C_.sty%2C_.bst_files%2C_and_I_want_to_put_them_in_a_folder_to_keep_my_project_uncluttered._But_my_project_is_not_finding_them_to_compile_correctly),
add the `latexmkrc` file and put this line into it (which is already part of the `latexmkrc` provided by the project):

```bash
$ENV{'TEXINPUTS'}='./src/:';
```