looking to invest in 2 family

[Chris Tom]

Hello i am new in to this forum.... i am interested in investing in realestate to make some money on the side i dont want to become a millionar just maybe buy and rent out a two family home where on floor pays for that mortage and the ohter floor goes into pocket or can pay another mortage. my question is can i have multiple mortages at one time? is there a time frame on which i can applay for a second mortage? also i seen these ads in my local newspaper saying they only want like 5000 d/n could that be possible all i would need is 5000 down? some ads say 5000 on contract what does that mean? i really only 5,000 to invest... any other information would be great thank you .