You Must Have The WEBNOVEL App Installed on an Android or iPhone device! Farming won't work on PC!
Enable Farming Mode by going to Profile > Settings > Farming mode and make sure it is on (blue; I presume you know how on/off toggles work). After that, go to Featured section (the one with the compass, next to the Library), and then click on the red FREE option in the top bar. On the page that opens, scroll down and you will see lists like Originals Farming and Fan-fic Farming.
You can choose a novel from those lists to read. Remember, to make sure you get ads (if you want points), just change the Reading mode to PAGING instead of SCROLLING, and start reading normally. To change from SCROLLING to PAGING, click in the middle of an open chapter, and the General screen will open. Choose Display, and select PAGING if it isn't selected already. Every 10-20 pages, you will get an ad that will give you +2 Farming Points. The more you read, the more points you earn, and the more stuff you can buy from the Points Store.
If you don't have it in you to search for novels to farm, I will recommend the following novels that have Farming enabled.
I Reincarnated As A Stick (IRAAS) — by TrueDawn -> 100+ Chapters | Original
Endless Path : Infinite Cosmos (EPIC) — by Einlion -> 1250+ Chapters | Fan-fic - Original
Monster Integration (A W) — by AnWan -> 450+ Chapters | Original
Journey Towards Greatness (PJTG) — by Evil_God_ZARAKH -> 350+ Chapters | Fan-fic - Original
Note: If your points don't increase after watching an ad, don't be worried. They are added to your account, the app just lags when updating them in real-time some times.