What's uploading? It's the action of copying a document from your computer (like an image, or a MS Word document, or a sound document, etc.) and placing it on another computer. In this case you're placing the copy onto the computer that runs your website so that you can use it on your website.
So you've clicked Browse, and you're presented with a new window that looks something like this:
This tool is like a filing cabinet. You can use it to look through various directories on your computer to find the desired documents.
When you've found the document you want
When you've found the document you wish to upload, select it and click Open. You'll know a document is selected if it's highlighted (usually in blue).
Clicking Open simply copies and pastes a "pathway" or a set of directions that tells Mainspring exactly what document you wish to upload. This set of directions looks something like C:Documents and SettingsEric JustianMy DocumentsClientsMainspringimage.jpg and should appear in the UPLOAD area on your Mainspring page after you've clicked Open
About the window
The center area of the File Upload window displays a set of files and documents. This is where you'll select the file you want.
On the left are buttons that will take you to the most common directories: your desktop, your My Documents directory, etc.
At the top is a drop down list that gives you a more comprehensive list of directories on your computer. Click it and the drop down list will expand giving you a list of directories on your computer.
On the bottom is a drop down list called File Name, click it and it will provide you with the same list of documents found in the larger area.
Below that is another drop down list called Files of Type. This can make your search easier by displaying only the type of document you want. For example, if you wan to upload an image file, you might click this drop down list and select .jpg if it's an option.