On the main page, just above the words "Message Index" is, of course, the main menu. Click on the link for [Search]. Click on the second radio button next to "Posted between 1 January 2007 and 6 February 2012. (This is all messages from the last 'archiving' to the most recent post). You can, of course, edit the date range if you know the particular time period such as the month of December or since the first of the year, etc.
The second section, "Search for", lets you choose based on words in the message, e.g. "bushwhacker". You can change the selection from "All" keywords to "Any" keywords to find spelling variations such as "bushwhacker" or "bushwacker". You can also search by the name or part of the name of the person who posted the message. (Unfortunately you can't search on both keywords and name at the same time). To search by name, select the last radio button and enter the name (or part of the name) for who posted the message. For example, if you searched for "Martin" you would get every post with 'Martin' in the name field, e.g. Ken, Jim, George, etc. Make sure to click the radio button next to your selections -- I often forget this and the software doesn't do it for you automatically. Of course the final step is to click the "Search Messages" button at the bottom.
On the main menu there is also a link for [Archives] which you can search from the beginning of time (Aug. 25, 2001 for the Indian Territory board) through Dec. 31, 2006. JWM (Jim the WebMaster, who is also my "double" 1st cousin) started History-sites.com and his first Civil War message board for Alabama in Sept 2000. There are now well over 30 message boards! My biased opinion is that the participants on these message boards have made these the best resource of its kind on the internet. I hadn't realized they were over ten years old! But I digress.
I can't answer why there aren't as many western Arkansas posts as other areas. There are certainly many interested in the area, including myself. My gg grandparents were married in Polk County in 1863 where there was a community of Cherokee and a number of Cherokee refugees during the war. There are three Cherokee from Polk County, including my gg grandfather, that are musterred in to the 13th KS Inf in Ft Smith in early 1864 (I assume involuntarily since all three deserted within a couple of months). One of these men was originally in the 4th AR Inf but didn't go east with them, presumably due to his age. My g great-uncle from Polk County was in the 4th AR Inf but shows up later in Watie's Regt. There were many men of western Arkansas in the Cherokee units, particularly Benton and Washington Counties. There were likely a number of Cherokee in Arkansas units. E.C. Boudinot was secretary of the Arkansas Secession Convention, then in a Fayetteville cavalry company that fought at Wilson's Creek, then became major in Watie's Regt, he was Hindman's vol adc at Prairie Grove, and then Cherokee delegate to the Confederate Congress. There were strong economic ties between the 'Southern' Cherokee and northwest Arkansas. Many Indians continued their education in 'the State', primarily Fayetteville and Cane Hill. Local residents used the grist mills that were closest to them such as Hildebrand's in the Cherokee Nation and Rhea's Mill and Dutch Mill in Arkansas. The units and "irregulars" of the area of course operated on both sides of the line. But back to your original question... I suggest you post more about western Arkansas! ;-)
Bryan posted late last year that he would be away from the messageboards doing some research so I assume that is why he is away. Bryan has such a wealth of knowledge on Arkansas units he is sorely missed! I spoke with Jim yesterday and he was going to contact Bryan and get an update.
Ken