Honestly I'm new to the lockpicking! I'm trying to gm lockpicking and have read online about practicing on a gm locked chest or box until 100 I believe that's what I need
You can use a GM made box until 95. After 95 the only way you can get gains is from level 4 chests from a tmap and from level 4 chests in dungeons. The rune library fort that’s near cove has 2 runebooks with all the chest spawns for level 4 dungeon chests in them. Be ready for a long grind from 95-GM.
Here is how I got my lockpicker to 95.0 within 1-3 days (Taken from One guide to Rule Them all) Raising Lockpicking: Lockpicking is a difficulty based skill. Use a lockpick on an appropriate difficult chest for a chance to gain skill. 0-30: Train from an NPC (tinkers) 30-50: Use a 30/30 player created locked box (create a new character with 30 tinker/30 carpentry) 50-76: Use a 50/50 player created locked box (create a new character with 50 tinker/50 carpentry) 76-82: From Pirul - Use a 70/70 player created locked box OR raise your Detect Hidden and use a GM box for a few points of Lockpicking, and then drop the Detect Hidden (Detect Hidden gives a 5% passive bonus to lockpicking) 82-95: Use a 100/100 player created locked box (sold at player shops) 95-GM: Level 4 Dungeon Chests Gideon's Advice: You can often find a player to purchase several hundred lockpicks from if they made them while training tinkering.