My new lovebird won't play with toys. How can I encourage her?

Thanks for your question about Zinnia. I didn't see how long you have had Zinnia, but part of the reason may be that she is nervous and adjusting to her new home/environment. I am not sure what types of toys you have present, but in the picture I could see some rope material, some wood, and some fibrous types of material. These are all very appropriate toys for a lovebird. Other options may include bells (ensure they are made of stainless steel, including the clapper, as heavy metal toxicity is a concern in birds), plastic (ensure that it is sturdy, as we don't want any ingestion of foreign materials!), and you can make homemade toys as well out of tissue paper (with no dyes) and toilet paper or paper towel rolls. To make these more interesting for Zinnia, you may need to play with the toys with her - of course, this will depend on how social she is with you. You can also incorporate food in with the toys to make them more appealing - this can be done using pellets or produce items. This will not only allow for her to have interaction with the toys, but will provide her with foraging opportunities, which is very important for our pet birds.
I hope that gives you a place to start, and congratulations on your new pet!