Siman 134
Presented here for study, not as a practical ruling. The Shulchan Aruch rules by Sephardi custom, the Rema's glosses by Ashkenazi custom, and the Kitzur follows Ashkenazi custom. For a practical question, ask your rabbi.
א הַגָּה: נוֹהֲגִין לְהַרְבּוֹת בְּתַחֲנוּנִים בְּשֵׁנִי וּבַחֲמִישִׁי, (טוּר) וְאוֹמְרִים: וְהוּא רַחוּם, וְאוֹמְרִים אוֹתוֹ בְּקוֹל רָם; וְאִם לֹא אֲמָרוֹ מְעֻמָּד, עוֹבֵר עַל הַתַּקָּנָה וְנִקְרָא פּוֹרֵץ גָּדֵר. הַגָּה: וְכֵן נוֹהֲגִין לְאָמְרוֹ מְעֻמָּד, אֲבָל אוֹמְרִים אוֹתוֹ בְּלַחַשׁ; וּמַה שֶּׁנּוֹהֲגִים לְהַרְבּוֹת בְּתַחֲנוּנִים בְּשֵׁנִי וּבַחֲמִישִׁי, מִשּׁוּם שֶׁהֵם יְמֵי רָצוֹן, וְלָכֵן נוֹהֲגִין גַּם כֵּן לְהִתְעַנּוֹת בָּהֶם (טוּר).
1 The Order of "V'hu Rachum" and Lifting The Torah. Containing 2 S'ifim: Rema: We practice to increase supplications on Monday and Thursday (Tur) and say "V'hu Rachum"; and it is said aloud. And if one did not say it while standing, he transgresses a [Rabbinic] enactment and it is called "breaching a fence". Rema: Indeed, we practice to say it while standing, but we say it quietly. And regarding what we practice - to increase supplications on Monday and Thursday, it is because they are days of [Divine] favor, and therefore we practice also to fast on them [Tur].
ב מַרְאֶה פְּנֵי כְּתִיבַת סֵפֶר תּוֹרָה לָעָם הָעוֹמְדִים לִימִינוֹ וְלִשְׂמֹאלוֹ, וּמַחֲזִירוֹ לְפָנָיו וּלְאַחֲרָיו, שֶׁמִּצְוָה עַל כָּל אֲנָשִׁים וְנָשִׁים לִרְאוֹת הַכְּתָב וְלִכְרֹעַ, וְלוֹמַר: וְזֹאת הַתּוֹרָה וְכו' תּוֹרַת ה' תְּמִימָה וְכו'. הַגָּה: וְנָהֲגוּ לַעֲשׂוֹת כֵּן אַחַר שֶׁקָּרְאוּ בַּתּוֹרָה, אֲבָל כְּשֶׁמּוֹצִיאִין אוֹתוֹ אוֹמֵר הַשְּׁלִיחַ צִבּוּר גַּדְּלוּ וְהַקָּהָל אוֹמְרִים רוֹמְמוּ כו' אַב הָרַחֲמִים [הוּא] יְרַחֵם עַם עֲמוּסִים וְכו'; וְיֵשׁ אוֹמְרִים לוֹמַר עַל הַכֹּל יִתְגַּדַּל (מ"ס פי"ד וְטוּר וּמַהֲרִי"ל) וְכֵן נוֹהֲגִים בְּיוֹם טוֹב וּבְשַׁבָּת; וְיֵשׁ לְהַחֲזִיק הַתּוֹרָה בְּיָמִין (מַהֲרִי"ל), וּכְשֶׁעוֹלֶה הָרִאשׁוֹן לִקְרוֹת אוֹמְרִים: בָּרוּךְ שֶׁנָּתַן תּוֹרָה כו' (כָּל בּוֹ).
2 One shows the writing of the Torah scroll to the people standing to one's right and to one's left, and then turns it to those in front of one and those behind one, for it is a mitzvah for all the men and women to see the writing and to bow and to say "V'zot Hatorah... Torat Hashem Temima etc." ("And this is the Torah... Hashem's Torah is Perfect etc."). Rema: And [Ashkenazim] practiced to do this after they read from the Torah, but when they remove it [from the Ark] they prayer leader says "Gad'lu" and the congregation answers "Romemu... Av Harachamim Hu Yeracheim Am Amusim etc." ("Exalt... May the Father of mercy have compassion on the people borne by Him etc."). And some say to say "Al Hakol Yit'gadal [Masechet Sofrim - chapter 14, and the Tur and Maharil] and this is what we practice on Yom Tov and Shabbat. And one [who carries the Torah] should hold the Torah on one's right (Maharil). And when the first one goes up to read, they say "Baruch Sh'natan Torah etc." (Blessed is the One who gave the Torah, etc.") [Kol Bo]