1- Walk up on the object and GA at the same time. If done correctly, you should move upwards as if you are doing a reverse crouch GA without crouch
2- Cancel GA, sling, or superjump etc. (depending on checkpoint) and/or hold angelic descent if needed
Consider the solution to be:
If you’re still stuck after attempting the possible solutions above, consider finding the map guide video in the Mercy Parkour Code Spreadsheet (Mercy Parkour Codes) to see the intended solution or join the Mercy Parkour Discord (Mercy Parkour Server) to ask for help.