The Vikings originated as a consequence of islamic sex slave trade and the Finno-Ugric water ways in what later became RussiaAcknowledgement: When Klevius took his university courses in English language they showed a play based on a Millennia old English text. What a surprise when he heard the same intonation etc as well as many words and word endings similar to the Finland Swedish dialect he grew up with in Sibbo, a place in Southern Finland that has got its name from Viking Sibbe and the Sibbe castle (Sibbesborg). Later studies of Beowulf and other old texts have confirmed the picture, English is old Swedish spiced with French Latin. Finger, hand, arm, fo(o)t, tå (toe) etc etc, could go on forever, are all Swedish words still in use. If you add old Swedish words and Finnish loan words it covers almost everything except Latin (and sometimes even that via even older words). Also consider the Swedish word 'god' (meaning good) which comes from the Finnish 'koti' (home) and Sami 'goahti' (home) and created both Gotland, Goths and God (as well as 'cottage' etc).
Btw, Beowulf also uses the old term 'Sibbe', which means family member/friend (compare 'sibling') and which also may be linked to 'Siberia'.
Bjarmia Finns had connections to Norway (compare Ottar), Ladoga Finns as well as Volga Bolgar. Southern bilingual Finland Swedes connected to Gotland.
For a background see Origin of the Vikings.
The only reason old Swedish (old Norse) speaking people got involved was that southern Finland was bilingual as it still is as the borderland between Indo-European and Finno-Ugric. And this was a time before the Slavs had entered what is now northern Russia which was entirely Finno-Ugric speaking down to the Kiev region.
You may also have wondered about why the Vikings used river boats to Britain etc. Well, they just continued the Finno-Ugric river boat tradition (which had been around for thousands of years which can be seen in e.g. old stone ship graves in Gotland) in a larger scale until people finally realized to go back to the Roman sea technology again after the Viking age..
The Viking sex slave trade to the Jews and the muslims started much earlier (before 750) in the east than when the first Vikings appeared in Britain (after 786), which fact most people are unaware of due to constant misinformation on Wikipedia etc.