Something straightforward, not intimidating or extreme, soft and adjustable would be a great starter point.

The simplest thing you may try is a pair of good cuffs. Soft touch, Tie me softly, Fantasy cuffs, Neck to wrists restrain set - all these products are just excellent for beginners. They have a pretty simple design, therefore, are easy to use and maintain. Meanwhile, they open a whole variety of options for your play.

If you wish to add a bit more, Soft bondage kit or even Satin fetish set may be an amazing option as they include not only cuffs for restraining your lover but also a few additional items for making your experience more exciting!

Oh, and also Under the bed kit is a fantastic product for BDSM play. Comfortable and simple to use, very adjustable and versatile, it could be a perfect fit!