Ihram, in fact, does not mean the wearing of the two sheets, but the period of Ihram will begin when you will recite the Taiba with the Niyyat (precise formulation of the intention) of the Haj or Umrah after offering up the two Raka’ats Namaz of Ihram.
It will be better to go by the practice of Tamattu. You should, therefore, after you have resolved to put on the Ihram, wrap one sheet of it like a loin-cloth and the other like a shoulder-cover after taking a good, clean bath (or performing the wazu if, due to one reason or another, you may not want to bathe) and then offer two Raka’ ats of Namaz, earnestly and reverentially, with your head covered by the shoulder-covering sheet of the Ihram. At the termination of the Namaz when you turn your face, pull down the sheet from the head, i.e. uncover your head, and, then, with the intention only of Umrah recite the Talbia loudly, in a full-throated manner.
The words of the Talbia are as follows:
لبيك اللهم لبيك Labbaika Allahumma Labbaik
لبيك لا شريك لك لبيك Labbaika, La Shareeka Laka, Labbaik
إن الحمد والنعمة Innal Hamdah, Wan Nematah,
لك والملك، لا شريك لك لبيك Laka wal Mulk, La Shareeka Laka Labbaik
“O, Allah! Here I am! Here I am! Thy presence! Thou hast no partner! Here I am! All praise is for thee and from thee are all blessings! To thee alone belongs power(and Rule)! Thou art without a partner!”
You should learn Taibia by heart and let its meaning sink into your consciousness. The Talbia should be recited with the conviction that it is being addressed to Allah and he is hearing it.
On offering up the two Raka’ats Namaz of Ihram and turning the face in salutation recite and Talbia with the intention of Umrah and pray to Allah that you are putting on the Ihram for the Umrah for His propitiation and beg Him to grant you the good fortune to perform the Umrah properly and to protect you against the mischief of the Satan and your own carnal self, and accept your Umrah.
Together with this, you may also make other good petitions to Allah, if you so desire.