How can I download and install Autocad 2013? And is there any good online tutorial about autocad 2013?

Lynda.com is one of the best sites where you can watch or download tutorial videos at a price. If you have a LinkedIn Premium account, you can make use of this service for free.

First of all ... did you paid for the program or do you just want a freebee?

If you purchased it there are specific instructions to download it and install it including the load keys.

Otherwise check with AutoDesk.com

You also can call them and check if there is a licens available for an employee ... ( I think they are called Home versions) you have to furnish a load key from your company and this license will be issued in your name ... a full version will be send to you ... at least that is how I got my Microstation software and license 

Below is link to download AutoDesk software from original web. But you need to purchase it after days trail.

http://autodesk.creativevirtual.com

•  Just go to > Download Links  and find your desired software and version. And download it with super speed.

OR

• Type your desired software in search box and submit below. You will find all related information immediately. 

there are plenty of them, just google it

Just search on google. http://www.autodesk.com/education/free-software/autocad you can use

From Autodesk Website. You have a trial version valid for 30 days afterwards you hve to buy it

Autocad 2013 can download from  Autodesk official site, but the latest one is 2016. 

MANY OF AUTOCAD VERSIONS HAVE INSTALLED FROM THE WEB SITE : SHARE LINK.COM

You can purchase the software online from Autodesk, download the software and install.

You can even find very good tutorials in Autodesk website itself. Otherwise google also comes very handy for tutorials.