How old is he now? When wanting to train for treats, put all toys away, maybe skip a meal and if needed keep a line on him so he can't run off.
Now to address your actual question. When starting with toys, keep everything up and exciting. Usually when I start to introduce toys into my work it's to pick the drive up. I use food for precision, and toys for enthusiasm. First thing is teaching him how to think when the toy is present. So it may not be anything too exciting at first. A sit and eye contact with him quiet, then BAM reward. Then maybe a couple paces of heeling, then BAM reward. Make the toy should just be the vehicle for him to engage with you. So once he has it, play with him. When I first start toy sessions, they are fast paced, short and sweet.
Here is a short video of my first toy obedience session with Winston. For whatever reason, I couldn't get him on treats, so I just went for the toy to get something out of him.
He just turned 6 months old. I used to use his entire lunch (kibble) to work on training everyday, and he used to be enthusiastic and all about it. He's since stopped being willing to work enthusiastically for kibble, even when he's hungry, so I've switched over to other treats. When I start a training session, all toys get put away, but then all he does is look for a toy and act generally distracted, even on leash.
An example of how I've been attempting to get him to work for a toy is when we play fetch. I used to just let fetch be fetch, but since he stopped being interested in training sessions, I try to get him to sit, down, spin, touch, whatever before I throw the ball. IF he manages to realize that I want a sit, he'll go into a half sit, meaning he's basically hovering over the ground and isn't fully sitting. Same with down. If I move, say anything, practically even blink, he's instantly up out of the half sit or down because he expects me to throw the ball (which I NEVER do). I can't lure him into the position or give him a minor correction because then he just stands up, stares at me, and whines.
He is 100% solid with his "out" command and instantly lets go of things when I ask him to. He knows with fetch to grab the ball and bring it back to my hand before I throw it again. He just gets so excited for me to throw it that he can't listen. If I try to use a tug toy, he gets bored pretty quickly and just wants me to throw that. He has no interest in playing with toys without me and is constantly pushing into me to play, so that isn't an issue. Maybe I'm just going about it wrong and he's confused?