Let's start with the gard part of Asgard. Gard, in ancient Germanic, referred to "fence" as in innangard and utangard. The innangard were those who lived inside the fence, they were the law-abiding, peaceful, civilized members of society. The utangard on the other hand were the those who lived beyond the fence, the uncivilized, wild, anarchic people. Asgard epitomizes the innangard and is the home of the Aesir, one of the two tribes of gods (the Vanir is the other tribe of gods). Asgard is located in the sunniest, highest branches of the world tree, Yggdrasil, and is accessed via Bifrost, the Rainbow Bridge, that connects Asgard with Midgard, our present abode
The Aesir were thought of as the powers that held the cosmos together. The most well known of the Aesir are Odin, Thor, Frigg, Tyr, Loki, Baldur, Heimdall, Idun and Bragi. We will take a look at some of them in a future blog post.
The only point of access to Asgard from Midgard where we reside is via Bifrost, the Rainbow Bridge, which is guarded by Heimdall on assignment from Odin. If you want to take a shmanic journey to Asgard then I recommend that your first gain the trust of Heimdall so that he will let you cross the Rainbow Bridge. Heimdall requires less sleep than a bird, has eyesight so keen that he can see for hundreds of miles by day or by night, and hearing so acute that he can hear grass growing on the ground and wool growing on sheep. Here he watches and listens, holding the horn Gjallarhorn or Resounding Horn at the ready, which he sounds when intruders are approaching. Don't think that just because you are taking a shamanic journey that you can sneak up on him or surprise him. I suggest an offering of ale, and an honest explanation of why you want to enter Asgard. He may not let you in the first time so visit frequently and gain his trust. I also recommend that you travel with a pure heart and without weapons. I find it foolhardy to try and intimidate, coerce, or surprise a Norse god.
I'm Dr. Dave, a modern druid. I lived and worked in Bolivia and Peru for over six years, where I and was trained by Andean Shamans, and today practice Druidcraft and contemporary shamanism.