["Parashiyot" - Portions from the Torah, written on parchment and inserted into the Tfillin.
"M'hadrim" - Those who perform the mitzvah in a superlative, but non-obligatory manner.]
34.1: (1) The order of the placement of the parashiyot in the Batim [inner compartments of the tfillin], according to Rashi and the Rambam, is first:
A) "Kadesh" ["Sanctify to Me all first-born", Ex. 13:1-10], in the left-most compartment (2) of the one wearing the tfillin [i.e., to the wearer's left], and after it
B) "Ki Y'viacha" ["When the L-rd shall bring you", Ex. 13:11-16] in the second compartment, and
C) "Sh'ma" ["Hear, O Israel", Deut. 6:4-9] in the third compartment, and
D) "V'Haya Im Shamoa" ["If you shall listen", Deut. 11:13-21] in the fourth compartment, which is the outermost on the wearer's righthand side.
(3) And according to Rabenu Tam, in the third compartment "V'Haya Im Shamoa", and in the fourth compartment which is the outermost, "Sh'ma". And the universal custom is (4) as Rashi and the Rambam.
34.2: A G-d-fearing man will fulfill his obligation according to both opinions and he will make two pairs of tfillin (5) and put on (6) both of them [simultaneously] and when he puts them on he will think: (7) "With those tfillin which are according to the law I [intend to] fulfill my obligation, and the others are like (8) mere straps [i.e., not tfillin of mitzvah]", for there is space on the head to put on two tfillin, and also on the arm. And if he is unable to set them in the proper place and put on (9) both of them together [because it is hard to fasten two tfillin simultaneously in one act], then (10) he should put on tfillin which are (11) according to one of the opinions [i.e., not one of Rashi and one of Rabenu Tam], (12) both hand-tfillin and head-tfillin (and remove them immediately)* and then put on the other pair on the basis of the blessing he said at the beginning [and not bless again on the second pair]. (And some say that)* if he is unable to put on [wear] both of them at the same time, he should put on the tfillin of Rashi and say the blessing on them and they should be on him during the recital of Sh'ma and Prayer [i.e., Shmoneh Esreh, Amidah], and after the prayer he should put on the tfillin of Rabenu Tam without a blessing and recite while wearing them "Sh'ma" and "V'Haya Im Shamoa" ["If you shall listen", Deut. 11:13-21].
* "and remove them immediately", "And some say that" - According to the Mishnah Brurah, these words should not be in the text of the Shulhan Aruch, although they are found in printed editions.
Siman 34 The Order in which the Torah Passages are Placed in the Tefilin (continued)
34:3 One should not conduct himself (16) in this manner [i.e., put on both Rashi and Rabbeinu Tam Tefilin], unless he is well known (17) for piety.
34:4 (18) One should not place two pairs (of Tefilin, i.e., one Rashi and one R. Tam) (19) in a single bag, since one of them (20) is non-sacred and it is forbidden to put it into a Tefilin bag. Rather he should make two bags, and label each bag so that he doesn't put the Tefilin that belong in one bag into the other bag.
[Presumably the intent here is that purchasing bags is alright, provided that one doesn't purchase a bag previously used for Rashi Tefilin and use it for his R. Tam Tefilin, and vice versa. Also, the term "non-sacred" ("Chol") in this context means lacking the sanctity _of Tefilin_; however, both pairs contain HaShem's name and must therefore be treated with appropriate sanctity. LC]