1. Open FH
2. Open Map Maker
3. Click Export. Get a piece of paper and a pen handy, you will need them. Tell it "yes" and it will start up a loading bar and exporting everything. Now if you're thinking "well I clicked that once before and I already did that so Im gonna go on" that does not matter. Do it again because odds are you have updated your map since then.
4. When its done it will tell you the following
"Exported object group as/Default.Fho" (Or it may end with "MyTrees.Fho" or "MyRocks.fho" etc. depending on what object group it picks first. It does not matter) What you need to do is write down on your piece of paper all of the names of these files.
5. Open your exports folder because this is where your list comes in handy. Right click, choose "create new zipped folder" and name it something appropriate for your map. Then once that is done, start locating all of the names of the files you wrote down earlier and copy and paste them inside of the zipped folder. Check them off as you put them in so you don't forget what is in there and what is not. (Because if you forget, something just might not show up)
6. Now you need an uploading website. I personally prefer Mediafire.com because I have experienced the least ad-related "attacks" on my computer thanks to googles ads. You need to upload your files to the website, which there will usually be an upload button BUT usually you have to make an account /before/ you can upload anything, so if you do, be sure to keep that password somewhere safe for later in case you decide to upload another map.
7.Once that's done, you can get the page with your download and copy the address in the address bar. Copy and paste the link from the address bar you copied and post it on your map thread. Likewise you can just send the address to whomever you want to download the map if you want it to be kept private.
NOTE: I provided these instructions with the assumption that you have a relatively recent Windows computer. If you have a mac or something slightly different, you may have to fool with it to figure out the similarities or post here and I'm sure someone with better experience can help you. But what I gave you should, in theory, work. ^_^; Hope it helps!