This is a tricky one.
I did mine by playing the map Sicily. Here is a link to a wiki page of the map itself.
https://dayofinfamy.fandom.com/wiki/SicilyGuide explanation:
Play online server, when you must choose a map, pick Sicily. Play as Axis and when round starts, run into the lower part of the middle bunker (hard to miss). Remember to bring smoke grenades, when the bots are almost near the bunker (you see/hear them), throw the smoke grenades in either passage way of the bunker sides, then hide against the wall and either wait for them to come in. You must need visual confirmation from bots so they track you in and look for you. Then stab them untill you get 5. You will have to likely run around and with some luck too in this. What worked for me was run outside the front bunker doorframe (There are two door frames on each side of the lower bunker) and stab the npcs when they are close. You usually have 1-2 seconds to get up to them and attack before they notice you and turn to face you/fire at you. Then run back in and hide and usually other npcs will follow you to track you down.
Explanation of what I did:
Now I did this on an online server with one other player being there and had allied bots too. The player had an MG and was nested in the first row of the buildings on the end of the beach and fired on the british bots coming up. I believe a officer bot also used smoke artillery which helped me a lot too.
As for what I did; The bunker on the beach is where I ran into and fired my weapon on the bots coming up the small hill-bumpy beach. Eventually I ran out of bullets and ran around with my knife. I survived by using the smoke clouds from the officers artillery and my own smoke grenades thrown on either passage entrance of the front of the bunker. And hid in the lower middle of the bunker on each side too at the doorframe openings. There is a tank inside which provides some cover too and you can rush the bots if they come around there too.