Space at the chainstay near the bottom bracket: figure out some way to space the fender tip out, closer to the tire. Easy if the chainstay bridge has an eyelet, slightly bothersome otherwise.

Space at the seatstay bridge: browse your local hardware store for appropriately sized drilled or slotted widget to go between the chainstay bridge and fender. Or ask you local shop if they have a short rack stay they can part with.

Once you get those two fixing points sorted, the rest should fall into place with the adjustable fender stays.