I found some sheets of Avery mini folded cards. I don't know how to use them. Is there a template somewhere?

I suggest you go to the Avery WEB site and download the Word template for your Avery label. Use this template, enter your text and then print, don't forget to place the blank Avery in your printer.
You can download the templates from this WEB site.
http://www.averyproducts.com.au/avery/en_au/Templates-%26-Software/Templates/?Ns=Rank

what is the make of your printer ?

Hello there!
Here is the tempalte for the 5302 tent cards http://www.avery.com/avery/en_us/Templates-%26-Software/Templates/Cards/Note-Cards/Mini-Card-_-Wide-4-per-sheet_Microsoft-Word.htm?N=0&refchannel=c042fd03ab30a110VgnVCM1000002118140aRCRD
You will be using microsoft word to type in what you need to. Here is a tutorial on how to use the templates. http://www.avery.com/avery/en_us/Templates-&-Software/Templates/How-to-Use-Templates.htm
Hope this helps! Click on the thumbs up if it did!

This can be done with settings through your word processing program. Assuming you are using Word:

Microsoft Word 2007
The newest version of Microsoft® Word now includes hundreds of Avery Templates for labels, business cards, dividers and more.

Find Avery Templates by selecting the Mailing tab at the top of the Microsoft® Office Word screen. Just choose Create > Labels > Options > Avery US Letter, then choose your template by selecting the correct Avery Product Code.

Access Pre-Designed Avery Templates that are available from Office Online by selecting the round Office button at the top left of the screen, selecting New and then choosing the Avery product type. Pre-designed templates for Avery business cards, greeting cards, dividers, labels, note cards and postcards are available.

Avery Wizard for Microsoft Office is a free download which inlcudes step-by-step instructions to format Avery labels. Trust this is helpful. :)

Avery DesignPro should get you printing quickly. (It's Free)

http://www.avery.com/avery/en_us/Templates-&-Software/Software/Avery-DesignPro-for-PC.htm

Try placing the business card sheet in the main paper bin instead of the manual feed or adjusting the print orientation from Portrait to Landscape or vice versa.

This is normally set through the page margins within the software you are using not the actual printer settings. MS Word has templates for various Avery labels, but I've found after loading the template you have to fine tune the margins for your printer. Use plain paper to print test pages and hold them over your card stock to check alignment.

there are software templates on the avery website. Maybe you can find the specific product you bought on the website and download a template that will help you print labels.

Where you going to get the card at?

It worked fine for us on an Epson. We printed about 40 sheets fed one at a time. Do not stack the sheets in the feed hopper, they stick together because of the magnetism.

There is no template because the material is not die cut. It is just full 8.5x11" sheet size.