If it's not already done,
download Sothatwemaybefree.cfg
Paste it on /SteamApps/common/Counter-Strike Global Offensive/csgo/cfg/

On CS:GO, click on Play -> Offline with bots -> Competitive
Pick a map
then click Go -> No bots
Once you have selected a side, open the console command and type exec sothatwemaybefree.cfg
Everything you need to know is explain in console.

Frequently Asked Questions

How to open the console ?

Activate the console in Help & Options -> Game Settings -> Enable developer console. This will then allow you to open the console using the tilde key (~ or ²).

How do i train on 128 Ticks server ?

Go on your Steam library, right click on CS:GO -> Properties -> Define launch options. Add -tickrate 128.

How do i know if my server is 64 or 128 ticks ?

Start your server and type net_graph 1 on console command. Now, just check values of up and cmd. To hide thoses informations, use net_graph 0

My own binds are gone ?!

Type exec config.cfg on console or restart your game.

How to train easily ? works well with Steam Browser, so instead of Alt-Tab, you can just toggle the Steam Overlay.