Jesus had been on the west side of the Jordan River. AT: "to the east side of the Jordan River" (See: [[rc://en/ta/man/translate/figs-explicit]])
# he stayed there
Jesus remained on the east side of Jordan for a short period of time. AT: "Jesus stayed there for several days" (See: [[rc://en/ta/man/translate/figs-explicit]])
# John indeed did no signs, but all the things that John has said about this man are true
"It is true that John did no signs, but he certainly did speak the truth about this man, who does signs."
# signs
These are miracles that prove that something is true or that give someone credibility.
# believed in
Here "believed in" means accepted or trusted what Jesus said was true.