For the map_fix folder, try to install it like you install addon cars. I'm not the author so I can't say 100% sure that it's the way, but I'll explain how below
• Use OpenIV, set up a mods folder (look that up if you need to, it's really simple stuff)
Using OpenIV, go to GTA V/mods/update/x64/dlcpacks/ and enable edit mode, top right-ish of the window.
• Put the map_fix folder inside the dlcpacks folder, so it looks like GTA V/mods/update/x64/dlcpacks/map_fix/dlc.rpf
• Go to GTA V/mods/update/update.rpf/common/data/ and (while in edit mode) right click on dlclist.xml and press Edit.
• Scroll towards the bottom. You should see a list of lines starting with <item> and after that, </paths> which starts before (less spaces at the start). You want to add a line to the item list, so make sure it's in line with the other <item> entries. Add the line
<Item>dlcpacks:/map_fix/</Item>
• Press save on the bottom right of the text editor.
*** If your game is crashing after adding items to the DLC, use this and follow it's instructions. It allows the game to use more memory and items, from what I understand, and fixed crashing for me https://www.gta5-mods.com/misc/gta-5-gameconfig-300-cars
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For the map_fix folder, try to install it like you install addon cars. I'm not the author so I can't say 100% sure that it's the way, but I'll explain how below
• Use OpenIV, set up a mods folder (look that up if you need to, it's really simple stuff)
Using OpenIV, go to GTA V/mods/update/x64/dlcpacks/ and enable edit mode, top right-ish of the window.
• Put the map_fix folder inside the dlcpacks folder, so it looks like GTA V/mods/update/x64/dlcpacks/map_fix/dlc.rpf
• Go to GTA V/mods/update/update.rpf/common/data/ and (while in edit mode) right click on dlclist.xml and press Edit.
• Scroll towards the bottom. You should see a list of lines starting with <item> and after that, </paths> which starts before (less spaces at the start). You want to add a line to the item list, so make sure it's in line with the other <item> entries. Add the line
<Item>dlcpacks:/map_fix/</Item>
• Press save on the bottom right of the text editor.
*** If your game is crashing after adding items to the DLC, use this and follow it's instructions. It allows the game to use more memory and items, from what I understand, and fixed crashing for me https://www.gta5-mods.com/misc/gta-5-gameconfig-300-cars
Good luck all <3