Well, it would help if you would write in a slightly more organized manner.
In WW2, there were 2 wars in which Finland participated.
The first was the so called Winter War, the USSR considered Leningrad to be unadequatly protected and demanded that the Finns cede territory, they offered some fairly worthless land in return. Finland refused leading to a full scale soviet invasion.
The Finns established a though static defense at the Mannerhein line, and used an elastic defense (constantly pepper the Russian while giving some ground) everwhere else. Russia logistic capacities were bad, and the fact that Russia used more troops than the land could support made it even worse. Last but not least, the Russian troops came from Southern Russia since Stalin did not trsut north Russians to fight against Finns. Mixed with an unusually hard Finnish winter, Russian casulties amounted to nearly half a million. Finnland was largely on its own, receiving some help from Norway and Sweden and well as token support by Germany. In the end, Russia had more soldiers than the Finns had ammunition and Finnland had to ask for terms. Assuming that occupying Finland would be hell, the Russians settled what they asked for in the beginning.
After barbarossa, Finland was eager to join the party in an effort to get back their territories. However, it was not total war on the side of the Finns, they did not attack Leningrad (they always maintained that Finnland does not threaten Leningrad) and only advanced upon area to which Finland had internationally legalized claims to. There were Germans operating from Finnland, but the Finnish gouverment always kept close control.
To their credit, the Finns utterly refused to send their Jews to the Germans.
When the war effort was failing, Finnland was eager for a seperate peace with the SU (while they were technically at war with the western allies, I am not aware of any military clashes), on of the Soviet demands was that Finnland interns all German troops, in response they could keep their independence. The German military caught wind of this and tried to stage a coup which failed. With their situation becoming untenable, the German began to retreat over Lappland to Norway, which was under German occupation. They did devastate soem villiages in Lappland (to prevent the Finns from following them in force), but allowed the population to evacuate beforehand. As far as I know, most Germans made it to Norway, the ones that the Finns captured were turned over to the SU later.