1.) What you want to do first is open the PIVX mobile wallet, on the top left select the 3 lines which will bring the options menu to the side.

2.) Select the Setting tag as show below.

3.) Now select change trusted node.

4.) You should see the PIVX furszy node, below it select "Add Node"

5.) Now you will need your nodes IP address or host name, Insert it in the host field, the IP field in most cases can be left blank and select "add node". I have used my own server for this 

Your wallet should now be connected to your node of choice, your balance may not show yet as it needs to synchronize with the new node, give it 5 - 15 minutes. To confirm that it is indeed working go to step 1 of this tutorial where you selected the 3 lines and in the menu you should see "synchronizing or synced below "wallet"