Assume that your installation is successful, if you are using Win 7, on the left bottom of your screen, click on start- then all program--in the drop down list, find the name Microsoft SQL server 2012 and click on it, you will find the SQL server Management stadio, clikc on it and you will open the SSMS (you log in either using window authentication or sql server authentication),
or after your find the SSMS, right click on it and SEND TO--DESKTOP(CREATE SHORTCUT), you will create a shortcut on your desktop, in the future you can click on this shortcut to log in SSMS
For the 2nd question I do not catch it, maybe you can change to Firefox browser and restart the download.
Hope this helps