Niko will request materials in the materials box on the second floor of the Paradise Planning building. Fulfill these requests to learn new DIY recipes.
Check the Requested Materials
After Niko requests materials for DIY, go to the second floor of the Paradise Planning building and check on the materials box on the left side of the room. You can check the list of requested materials to see what is needed.
Contribute the Requested Materials
If you have the necessary materials in your home storage, you can use the home storage cabinet on the second floor of the Paradise Planning building to get them. The cabinet is to the left of the mirror.
Once you have some or all of the required materials, check on the materials box and choose to contribute materials, then select the materials from your inventory. If you don't have all of the materials, you can make multiple contributions until you have contributed all the required materials.
Receive new DIY from Niko
The next day, Niko will give you the new DIY recipes the first time you go to work. Be sure to check the materials box after this, because Niko may have a new request.