An easy format I have come up with to do this without any external program with the falling sand method is to start with this command
summon FallingSand ~ ~1 ~ {Time:1,Block:redstone_block,Riding:{id:FallingSand,Time:1,Block:command_block,TileEntityData:{Command:____},Riding:{}}}
and insert your first command into "{Command:____}", replacing the ____, and then copy this:
id:FallingSand,Time:1,Block:redstone_block,Riding:{id:FallingSand,Time:1,Block:command_block,TileEntityData:{Command:____},Riding:{}}
into the brackets at the rightmost "Riding{}" and enter the next command into the next "{Command:____}". Once you have entered in all your commands, you need to delete the last Riding{}, or the command won't run. Keep in mind that the commands will execute in the reverse order than what you input them in.
If you want to delete the extra block spawned or even the original command block itself as well, then start with this command
summon FallingSand ~ ~1 ~ {Time:1,Block:redstone_block,Riding:{id:FallingSand,Time:1,Block:command_block,TileEntityData:{Command:/fill ~ ~1 ~ ~ ~-? ~ air},Riding{}}
and replace the question mark at "~ ~-? ~" with 2 * the amount of commands you used and add to that 2 if you want to leave the original command block or 3 if you only want to run it once and then delete it.
FallingSand
, which as I understand it is the old, deprecated version offalling_block
, so his command won't work in 1.14. I have been testing it for a bit and I can guarantee that all the commands in the command block minecarts are effectively run in Minecraft 1.14, and as far as my research showed, this hack it is the only way to run multiple commands from one command block.