History of the Puritans, Vol. 1 (1843 ed.), pp. 461-462:
The Assembly was opened on Saturday, July 1, 1643, with a sermon preached by Dr. [William] Twisse. The ordinance for their convention was then read, and the names of the members called over, after which they adjourned to Monday, and agreed on the following rules:
(1.) "That every session begin and end with a prayer.
(2.) "That after the first prayer, the names of the Assembly be called over, and those that are absent marked ; but if any member comes in afterward, he shall have liberty to give in his name to the scribes.
(3.) "That every member, before his admission to sit and vote, do take the following vow or protestation:
"I, A. B., do seriously and solemnly, in the presence of Almighty God, declare that, in this Assembly whereof I am a member, I will not maintain anything in matter of doctrine but what I believe in my conscience to be most agreeable to the Word of God; or in point of discipline, but what I shall conceive to conduce most to the glory of God, and the good and peace of his Church."
And, to refresh their memories, this protestation was read in the Assembly every Monday morning.
(4.) "That the appointed hour of meeting be ten in the morning; the afternoon to be reserved for committees.
(5.) "That three of the members of the Assembly be appointed weekly as chaplains; one to the House of Lords, another to the House of Commons, and a third to the committee of both kingdoms. The usual method was to take it by turns, and every Friday the chaplains were appointed for the following week.
(6.) "That all the members of the Assembly have liberty to be covered, except the scribes," who some time after had also this liberty indulged them.
Besides these, the Parliament, on the Thursday following, sent them some farther regulations. As,
(1.) "That two assessors be appointed with the prolocutor, to supply his place in case of absence or sickness, viz., Dr. Cornelius Burges [Burgess], and the Rev. Mr. John White, of Dorchester.
(2.) " That scribes be appointed, who are not to vote in the Assembly, viz., the Rev. Mr. [Henry] Roborough and Mr. [Adoniram] Byfield.
(3.) "That every member, on his first entrance into the Assembly, take the fore-mentioned protestation.
(4.) "That no resolution be given upon any question the same day wherein it was first proposed.
(6.) "What any man undertakes to prove as a necessary truth in religion, he shall make good from the Holy Scriptures.
(6.) "No man shall proceed in any dispute after the prolocutor has enjoined him silence, unless the Assembly desire he may go on.
(7.) "No man shall be denied the liberty of entering his dissent from the Assembly, with his reasons for it, after the point has been debated; from whence it shall be transmitted to Parliament, when either house shall require it.
(8.) "All things agreed upon and prepared for the Parliament shall be openly read, and allowed in the Assembly, and then offered as their judgment, if the majority assent; provided that the opinions of the persons dissenting, with their reasons, be annexed, if they desire it, and the solution of those reasons by the Assembly."
Larry Holley notes further in his unpublished dissertation, The Divines of the Westminster Assembly: A Study of Puritanism and Parliament (1979), Appendix III, p. 225, that an additional rule was propounded by the House of Lords on June 29, 1643, but rejected by the House of Commons on July 6:
No long Speeches to be permitted, that Matters may not be carried by impertinent Flourishes; but all Debates to be by Way of Argument, soberly and gravely managed.