Explanation of minimal spanning tree

The table below shows the order in which nodes are added to the minimal spanning tree rooted at node 0. In each iteration, a new node is added to the tree, and the distance to that node from all nodes adjacent to it are updated. Refresh the page to see another randomly generated unweighted graph.

0123456789
0infinfinfinfinfinfinfinfinf
0infinfinfinf2infinfinfinf
0inf3infinf210infinfinf
0inf3inf6210inf19inf
0inf3inf62247inf
0238622472
0232622472
0232622472
0232622472
0232622412