Yevamos 5:4 - 5:5

צריכות שני גיטין – for both Yevamot/widows whose husbands died without children according to the Rabbis for there is a statement [of intention of the levir] after a statement [of intention of the levir].

וחליצה – to one of them and this exempts her rival/co-wife.

מאמר לזו וגט ולזו – the Jewish bill of divorce to the latter [wife] invalidates that of the first [wife] he has been declared as one “who will not build up [his brother’s house]” (Deuteronomy 25:9 – see Talmud Yevamot 32a), and she requires a Jewish bill of divorce for his declaration [of intention for levirate marriage] and Halitzah for his levirate connection.

מאמר לזו ובעל לזו צריכות שני גיטין – for this one, a Jewish bill of divorce for his declaration [of intention for levirate marriage] and for the other [woman] a Jewish bill of divorce for his act of coition.

וחליצה – to one of them and this exempts her rival/co-wife.

גט לזו ובעל לזו צריכות גט וחליצה – and it is prohibited to sustain her for he has been declared as one “who will not build up [his brother’s house]” (Deuteronomy 25:9), because of the first Jewish bill of divorce. But with a Jewish bill of divorce by itself, does not free woman who had a sexual act because it was a disqualifying act of coition.

אין לאחר חליצה כלום – and if afterwards he betrothed her or her rival/co-wife, Kiddushin/betrothal does not take effect with her, as per Rabbi Akiva, who said that Kiddushin does not take effect in those who are liable for violation of negative commandments, but it is not the Halakha.

חלץ וחלץ – he is permitted [to be married to] the relatives of the second [woman] for there is nothing after the first Halitzah any levirate connections, and Halitzah with both is nothing, for even to the priesthood, she is not invalidated. And similarly, if he performed Halitzah with the first [widow of the deceased childless brother] and made a statement [of intention of levirate marriage] with the second [widow], and similarly, if he had given a Jewish bill of divorce to this [second] one after performing Halitzah with that one, or performed an act of coition with this one after the Halitzah of that one, the act with the latter person is not worthless. [Or] if he performed an act of coition with this one first and then returned and performed an act of coition with the second, or performed an act of coition first and then made a statement [of intention of levirate marriage] with the second , or gave a Jewish bill of divorce to the second, or performed Halitzah with the second, there is nothing after an act of coition at all, and the final act is not considered, and he is permitted with the second’s [female] relatives.

אין אחר חליצה כלום – It is referring to the first clause [of the Mishnah], but regarding the concluding clause, it is necessary to state that there is nothing after an act of coition.