How to set directory in htaccess?

Question

htaccess

Wrote RewriteEngine rules

RewriteRule ^jump.php jump.php [L,QSA]
RewriteRule ^(.*) index.php [L,QSA]

But the following happens:
when the page accesses one of the files (css, js ..),
then, according to the conditions, the request goes to the root of
the file

http://website/assets/js/underscore.map

does not connect to the site, because htaccess redirects the request from `assets` to index.php
how to write a condition so that requests containing /assets/ fall into assets?
And advise something to read to deal with htaccess)
Preferably something short and only to the point.

Answer 1

1 is short and doesn't work. mod_rewrite works in a rather specific way.
2. what to read https://habrahabr.ru/company/sprinthost/blog/129560/
further, this rule does not make much sense, what did you want to do with it?
and this rule redirects all requests to index
A L - it doesn't work as you think.
As far as I understand, this is your attempt to create a cnc

RewriteCond %{REQUEST_FILENAME} !-f
#! - отрицание , не файл
  RewriteCond %{REQUEST_FILENAME} !-l
# и не линка
  RewriteCond %{REQUEST_FILENAME} !-d
#  и не директория 
  RewriteCond %{REQUEST_FILENAME} !(.*)\.(css\|js\|html)$  
#   это прям если исключать по маске 
RewriteRule ^(.*)$ /index.php [L,QSA]
# после  любое количества cond идет rule  конды создают условия рул выполняет,