Today i decided to make this guide because when I use installous many links such as mediafire etc. does not install the app, only download the same and places them in this directory:
Simple, open ifile, follow the directory for find the file, click on edit, select file, click on notepad and copy file/link
now follow this directory:
Mobile/ Documents/ Downloads/ Installous/ Downloadsand paste your file.
now open installous, in the download page u can see your file, click on it and install
This is all, You can use this method also to download app directly from your iphone using app browser that have a download manager