Adsense Help Needed

Hi guys.

Im kinda new in this field so dont judge me.

I bought a nice micro niche website. Looks pretty OK.
Before adding the adsense code I have places in website where I have this text :

Your ads will be inserted here by
Easy Plugin for AdSense.
Please go to the plugin admin page to
Paste your ad code OR
Suppress this ad slot.

Now I need to add the adsense code to the website.
I insert the code to 3 different places in Easy plugin for Adsense. (or should I make 3 difeerent ads in adsesns?)
After saving this text what I mentioned before disappears.

What I do wrong or what Im missing?

Thanks for help!