I'm having trouble playing this. This is my first time playing a video and a subtitle from separate files and this is much harder than I expected. I downloaded the latest VSfilter and installed it no problem but still can't get the subtitles to show up in VLC or MPC. It works in KMP but the font is all big and when I tried to edit the subtitle font size it shows it even bigger and the subtitles start flashing awkwardly.
Use mpc. Right click the running video,->filters, check if directvobsub(autoloading version) is loaded. Probably not though. Right click, options, external filters, add filter, directvobsub. (If it's not there you didn't install it.) Add it, doubleclick on it to open the settings. General settings "load when needed". If the problem's not that it was set to "don't load" then I can't help you right now.
they were in the same folder, just not the same name.. I thought I could just load it manually in the player
anyway it worked for BS player but the subtitles were ugly
There are players (like VLC) that use bad internal filters that can't properly display ass subs. That's why you should use a so called directshow player like mpc, wmp or zp (disable any internal subtitlefilters if necessary) and confirm you're using directvobsub filter.
Also the main style of the script is called default which under certain circumstances (fiddling with vobsub's settings during playback) seems to cause the main style to reset to direcvobsub's default style (which is called -you guessed it- default as well). So if that happened to you, change directvobsubs text settings on the main page from default to Vietnamese or whatever and restart the player. If that doesn't help you then use these subs with a renamed main style.
Also there are a ton of playback guides on the net. I've linked to some of them in one of the older threads so go there if you have any other problems.