[bwdbrn1]

Welcome to the forum. Congratulations on your new yard, and your new to you rider, but darn the luck anyway! Take a look along the length of that chain to see if there is a thing called a master link. The picture at the bottom is what one looks like when it's apart. If there is one, that "U" shaped clip can be pried off with a screwdriver. It sits in grooves on the two long prongs. Once it is off, you can lift the oval shaped piece with the two holes off, then slip the main piece out of the chain and the chain will come off. If there isn't a master link, then you will simply have to cut the chain off of the mower with a hack saw, or bolt cutters work real well too.

So far as the model number and such, take a look at Toro's web site. There is help in locating the model and serial number, things you'll have to have when it comes time to get parts.

https://homeownersolutions.toro.com...y/product_center/225/model_serial__help/30033

Once you have your model and serial number, you can download an owner's manual from their site as well. Unless you have a Mac like me, then you can ask for one to be emailed to you by contacting their customer service.
https://homeownersolutions.toro.com...rol=SetCommunity&CommunityID=225&PageID=30034

Good luck with getting that Toro up and mowing again. Let us know how things are going for you.