Make sure you have a “data analysis” option under your Tools menu; if not you will have to load the add-on, which you can also learn from help.

You will have one column of data, and one column of “bins”. for histograms, your bins give the range of data that will be put into each bar. For example, if your bin column is 0,1,2,3 etc., the histogram will plot the #of data points it finds between 0 and 1 as one bar, between 1 and 2 as the next bar, etc. Try and make a column of made up data like the numbers one, two and three or something and see if it is working like you think.

Also, to make the bars touch each other, on any bar graph, right click on one of the bars, format data series, and under options, mess with the overlap and gap width to make it look like you want.