Bandwidth Control on PTCL Guest Network

Okay, so here is the complete background:
I’m using PTCL broadband in my home. I have two storey house and have put the upper storey for rent. I promised him Wi-Fi connection but I’m afraid he might download movies/games or share password with others ultimately making MY connection unusable/too slow. I read somewhere that I can set up a guest network through my router settings and limit the speed of that guest network. I have successfully set up a guest network but I can’t find any bandwidth control option for that specific guest network which ultimately defeats the whole purpose of it. I was hoping to limit the download speed of that network to a specific amount and then give him the password of that network so he could do whatever he want with it without affecting my network. Either I’m missing something or there is no such option like that in PTCL router (because I saw a video of some other router with that option). So, here I’m to find some guidance on this forum. Is there any option like this in PTCL router hidden somewhere or is it really missing? Thanks.
I’m using Tenda D301 router from PTCL.