Steps to Install:

Step 1: *THIS STEP IS HIGHLY RECOMMENDED*

Since this .xml file brings more pedestrians and a few added objects for the MLO interior of Yellow Jack Inn bar, so in order 
for this file to work you will have to first install the following two MLO interiors by Bamboozled:

a) Yellow Jack Extension Interior (Single Floor Only) 2.0
Link: https://www.gta5-mods.com/maps/mlo-yellow-jack-extension-interior

b) https://www.gta5-mods.com/maps/mlo-yellow-jack-extension-interior-2nd-floor
Link: https://www.gta5-mods.com/maps/mlo-yellow-jack-extension-interior-2nd-floor

Step 2: Install Map Editor 2.13 script by Guadmaz
Link: https://www.gta5-mods.com/scripts/map-editor

Step 3: Go to 'Yellow Jack Inn - Enhanced & Alive' and copy 'yellowjackinn.xml' to your Grand Theft Auto 5 main directory.

Step 4: Run the game, press F7 to open up the Map Editor script & load yellowjackinn.xml.

Step 5: Visit Yellow Jack Inn bar & have some drinks in there.